I had the same problem, only mine stopped working all together in the end! I tried my other ipod, same 'No CD' message displayed. I took it back to VW and they ended up replacing it, or some part of it anyway. They said that if you don't use the correct plastic packing bits and the ipod is a bit loose in the dock, it can brake the small contacts on the adapter. The ipod vibrates and wiggles around a bit as you drive around. So now I use a bigger plastic thingy and the ipod is much more secure in the dock.